
<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>Canvas粒子图形变形动画特效 - 站长素材</title>

    <script type="text/javascript" src="js/jquery-1.7.2.js"></script>

    <style>
        html,body {
            width: 100%;
            height: 100%;
            margin: 0;
            padding: 0;
            overflow: hidden;
        }
        .container{
            width: 100%;
            height: 100%;
            margin: 0;
            padding: 0;
            background-color: #000000;
        }</style>
</head>
<body>

<div id="jsi-particle-container" class="container"></div>

<script>
    var RENDERER = {
        PARTICLE_COUNT : 1000,
        PARTICLE_RADIUS : 1,
        MAX_ROTATION_ANGLE : Math.PI / 60,
        TRANSLATION_COUNT : 500,

        init : function(strategy){
            this.setParameters(strategy);
            this.createParticles();
            this.setupFigure();
            this.reconstructMethod();
//            this.bindEvent();
            this.drawFigure();
        },
        setParameters : function(strategy){
            this.$window = $(window);

            this.$container = $('#jsi-particle-container');
            this.width = this.$container.width();
            this.height = this.$container.height();

            this.$canvas = $('<canvas />').attr({width : this.width, height : this.height}).appendTo(this.$container);
            this.context = this.$canvas.get(0).getContext('2d');

            this.center = {x : this.width / 2, y : this.height / 2};

            this.rotationX = this.MAX_ROTATION_ANGLE;
            this.rotationY = this.MAX_ROTATION_ANGLE;
            this.strategyIndex = 0;
            this.translationCount = 0;
            this.theta = 0;

            this.strategies = strategy.getStrategies();
            this.particles = [];
        },
        createParticles : function(){
            for(var i = 0; i < this.PARTICLE_COUNT; i ++){
                this.particles.push(new PARTICLE(this.center));
            }
        },
        reconstructMethod : function(){
            this.setupFigure = this.setupFigure.bind(this);
            this.drawFigure = this.drawFigure.bind(this);
            this.changeAngle = this.changeAngle.bind(this);
        },
//        bindEvent : function(){
//            this.$container.on('click', this.setupFigure);
//            this.$container.on('mousemove', this.changeAngle);
//        },
        changeAngle : function(event){
            var offset = this.$container.offset(),
                x = event.clientX - offset.left + this.$window.scrollLeft(),
                y = event.clientY - offset.top + this.$window.scrollTop();

            this.rotationX = (this.center.y - y) / this.center.y * this.MAX_ROTATION_ANGLE;
            this.rotationY = (this.center.x - x) / this.center.x * this.MAX_ROTATION_ANGLE;
        },
        setupFigure : function(){
            for(var i = 0, length = this.particles.length; i < length; i++){
                this.particles[i].setAxis(this.strategies[this.strategyIndex]());
            }
            if(++this.strategyIndex == this.strategies.length){
                this.strategyIndex = 0;
            }
            this.translationCount = 0;
        },
        drawFigure : function(){
            requestAnimationFrame(this.drawFigure);

            this.context.fillStyle = 'rgba(0, 0, 0, 0.2)';
            this.context.fillRect(0, 0, this.width, this.height);

            for(var i = 0, length = this.particles.length; i < length; i++){
                var axis = this.particles[i].getAxis2D(this.theta);

                this.context.beginPath();
                this.context.fillStyle = axis.color;
                this.context.arc(axis.x, axis.y, this.PARTICLE_RADIUS, 0, Math.PI * 2, false);
                this.context.fill();
            }
            this.theta++;
            this.theta %= 360;

            for(var i = 0, length = this.particles.length; i < length; i++){
                this.particles[i].rotateX(this.rotationX);
                this.particles[i].rotateY(this.rotationY);
            }
            this.translationCount++;
            this.translationCount %= this.TRANSLATION_COUNT;

            if(this.translationCount == 0){
//                this.setupFigure();
            }
        }
    };
    var STRATEGY = {
        SCATTER_RADIUS :150,
        CONE_ASPECT_RATIO : 1.5,
        RING_COUNT : 5,

        getStrategies : function(){
            var strategies = [];

            for(var i in this){
                if(this[i] == arguments.callee || typeof this[i] != 'function'){
                    continue;
                }
                strategies.push(this[i].bind(this));
            }
            return strategies;
        },
        createSphere : function(){
            var cosTheta = Math.random() * 2 - 1,
                sinTheta = Math.sqrt(1 - cosTheta * cosTheta),
                phi = Math.random() * 2 * Math.PI;

            return {
                x : this.SCATTER_RADIUS * sinTheta * Math.cos(phi),
                y : this.SCATTER_RADIUS * sinTheta * Math.sin(phi),
                z : this.SCATTER_RADIUS * cosTheta,
                hue : Math.round(phi / Math.PI * 30)
            };
        },
        createTorus : function(){
            var theta = Math.random() * Math.PI * 2,
                x = this.SCATTER_RADIUS + this.SCATTER_RADIUS / 6 * Math.cos(theta),
                y = this.SCATTER_RADIUS / 6 * Math.sin(theta),
                phi = Math.random() * Math.PI * 2;

            return {
                x : x * Math.cos(phi),
                y : y,
                z : x * Math.sin(phi),
                hue : Math.round(phi / Math.PI * 30)
            };
        },
        createCone : function(){
            var status = Math.random() > 1 / 3,
                x,
                y,
                phi = Math.random() * Math.PI * 2,
                rate = Math.tan(30 / 180 * Math.PI) / this.CONE_ASPECT_RATIO;

            if(status){
                y = this.SCATTER_RADIUS * (1 - Math.random() * 2);
                x = (this.SCATTER_RADIUS - y) * rate;
            }else{
                y = -this.SCATTER_RADIUS;
                x = this.SCATTER_RADIUS * 2 * rate * Math.random();
            }
            return {
                x : x * Math.cos(phi),
                y : y,
                z : x * Math.sin(phi),
                hue : Math.round(phi / Math.PI * 30)
            };
        },
        createVase : function(){
            var theta = Math.random() * Math.PI,
                x = Math.abs(this.SCATTER_RADIUS * Math.cos(theta) / 2) + this.SCATTER_RADIUS / 8,
                y = this.SCATTER_RADIUS * Math.cos(theta) * 1.2,
                phi = Math.random() * Math.PI * 2;

            return {
                x : x * Math.cos(phi),
                y : y,
                z : x * Math.sin(phi),
                hue : Math.round(phi / Math.PI * 30)
            };
        }
    };
    var PARTICLE = function(center){
        this.center = center;
        this.init();
    };
    PARTICLE.prototype = {
        SPRING : 0.01,
        FRICTION : 0.9,
        FOCUS_POSITION : 300,
        COLOR : 'hsl(%hue, 100%, 70%)',

        init : function(){
            this.x = 0;
            this.y = 0;
            this.z = 0;
            this.vx = 0;
            this.vy = 0;
            this.vz = 0;
            this.color;
        },
        setAxis : function(axis){
            this.translating = true;
            this.nextX = axis.x;
            this.nextY = axis.y;
            this.nextZ = axis.z;
            this.hue = axis.hue;
        },
        rotateX : function(angle){
            var sin = Math.sin(angle),
                cos = Math.cos(angle),
                nextY = this.nextY * cos - this.nextZ * sin,
                nextZ = this.nextZ * cos + this.nextY * sin,
                y = this.y * cos - this.z * sin,
                z = this.z * cos + this.y * sin;

            this.nextY = nextY;
            this.nextZ = nextZ;
            this.y = y;
            this.z = z;
        },
        rotateY : function(angle){
            var sin = Math.sin(angle),
                cos = Math.cos(angle),
                nextX = this.nextX * cos - this.nextZ * sin,
                nextZ = this.nextZ * cos + this.nextX * sin,
                x = this.x * cos - this.z * sin,
                z = this.z * cos + this.x * sin;

            this.nextX = nextX;
            this.nextZ = nextZ;
            this.x = x;
            this.z = z;
        },
        rotateZ : function(angle){
            var sin = Math.sin(angle),
                cos = Math.cos(angle),
                nextX = this.nextX * cos - this.nextY * sin,
                nextY = this.nextY * cos + this.nextX * sin,
                x = this.x * cos - this.y * sin,
                y = this.y * cos + this.x * sin;

            this.nextX = nextX;
            this.nextY = nextY;
            this.x = x;
            this.y = y;
        },
        getAxis3D : function(){
            this.vx += (this.nextX - this.x) * this.SPRING;
            this.vy += (this.nextY - this.y) * this.SPRING;
            this.vz += (this.nextZ - this.z) * this.SPRING;

            this.vx *= this.FRICTION;
            this.vy *= this.FRICTION;
            this.vz *= this.FRICTION;

            this.x += this.vx;
            this.y += this.vy;
            this.z += this.vz;
            return {x : this.x, y : this.y, z : this.z};
        },
        getAxis2D : function(theta){
            var axis = this.getAxis3D(),
                scale = this.FOCUS_POSITION / (this.FOCUS_POSITION + axis.z);

            return {x : this.center.x + axis.x * scale, y : this.center.y - axis.y * scale, color : this.COLOR.replace('%hue', this.hue + theta)};
        }
    };
    $(function(){
        RENDERER.init(STRATEGY);
    });
</script>

<div style="text-align:center;margin:50px 0; font:normal 14px/24px 'MicroSoft YaHei';color:#ffffff">
    <p>适用浏览器：360、FireFox、Chrome、Opera、傲游、搜狗、世界之窗. 不支持Safari、IE8及以下浏览器。</p>
    <p>来源：<a href="http://sc.chinaz.com/" target="_blank">站长素材</a></p>
</div>
</body>
</html>